3 files changed, 86 insertions, 2 deletions
diff --git a/src/view/com/composer/text-input/TextInput.tsx b/src/view/com/composer/text-input/TextInput.tsx
index 17f9513b7..20be585c2 100644
--- a/src/view/com/composer/text-input/TextInput.tsx
+++ b/src/view/com/composer/text-input/TextInput.tsx
@@ -190,12 +190,11 @@ export const TextInput = forwardRef(function TextInputImpl(
     let i = 0
 
     return Array.from(richtext.segments()).map(segment => {
-      const isTag = AppBskyRichtextFacet.isTag(segment.facet?.features?.[0])
       return (
         <Text
           key={i++}
           style={[
-            segment.facet && !isTag ? pal.link : pal.text,
+            segment.facet ? pal.link : pal.text,
             styles.textInputFormatting,
           ]}>
           {segment.text}
diff --git a/src/view/com/composer/text-input/TextInput.web.tsx b/src/view/com/composer/text-input/TextInput.web.tsx
index 199f1f749..c62d11201 100644
--- a/src/view/com/composer/text-input/TextInput.web.tsx
+++ b/src/view/com/composer/text-input/TextInput.web.tsx
@@ -23,6 +23,7 @@ import {Portal} from '#/components/Portal'
 import {Text} from '../../util/text/Text'
 import {Trans} from '@lingui/macro'
 import Animated, {FadeIn, FadeOut} from 'react-native-reanimated'
+import {TagDecorator} from './web/TagDecorator'
 
 export interface TextInputRef {
   focus: () => void
@@ -67,6 +68,7 @@ export const TextInput = React.forwardRef(function TextInputImpl(
     () => [
       Document,
       LinkDecorator,
+      TagDecorator,
       Mention.configure({
         HTMLAttributes: {
           class: 'mention',
diff --git a/src/view/com/composer/text-input/web/TagDecorator.ts b/src/view/com/composer/text-input/web/TagDecorator.ts
new file mode 100644
index 000000000..d820ec3f0
--- /dev/null
+++ b/src/view/com/composer/text-input/web/TagDecorator.ts
@@ -0,0 +1,83 @@
+/**
+ * TipTap is a stateful rich-text editor, which is extremely useful
+ * when you _want_ it to be stateful formatting such as bold and italics.
+ *
+ * However we also use "stateless" behaviors, specifically for URLs
+ * where the text itself drives the formatting.
+ *
+ * This plugin uses a regex to detect URIs and then applies
+ * link decorations (a <span> with the "autolink") class. That avoids
+ * adding any stateful formatting to TipTap's document model.
+ *
+ * We then run the URI detection again when constructing the
+ * RichText object from TipTap's output and merge their features into
+ * the facet-set.
+ */
+
+import {Mark} from '@tiptap/core'
+import {Plugin, PluginKey} from '@tiptap/pm/state'
+import {Node as ProsemirrorNode} from '@tiptap/pm/model'
+import {Decoration, DecorationSet} from '@tiptap/pm/view'
+
+function getDecorations(doc: ProsemirrorNode) {
+  const decorations: Decoration[] = []
+
+  doc.descendants((node, pos) => {
+    if (node.isText && node.text) {
+      const regex = /(?:^|\s)(#[^\d\s]\S*)(?=\s)?/g
+      const textContent = node.textContent
+
+      let match
+      while ((match = regex.exec(textContent))) {
+        const [matchedString, tag] = match
+
+        if (tag.length > 66) continue
+
+        const [trailingPunc = ''] = tag.match(/\p{P}+$/u) || []
+
+        const from = match.index + matchedString.indexOf(tag)
+        const to = from + (tag.length - trailingPunc.length)
+
+        decorations.push(
+          Decoration.inline(pos + from, pos + to, {
+            class: 'autolink',
+          }),
+        )
+      }
+    }
+  })
+
+  return DecorationSet.create(doc, decorations)
+}
+
+const tagDecoratorPlugin: Plugin = new Plugin({
+  key: new PluginKey('link-decorator'),
+
+  state: {
+    init: (_, {doc}) => getDecorations(doc),
+    apply: (transaction, decorationSet) => {
+      if (transaction.docChanged) {
+        return getDecorations(transaction.doc)
+      }
+      return decorationSet.map(transaction.mapping, transaction.doc)
+    },
+  },
+
+  props: {
+    decorations(state) {
+      return tagDecoratorPlugin.getState(state)
+    },
+  },
+})
+
+export const TagDecorator = Mark.create({
+  name: 'tag-decorator',
+  priority: 1000,
+  keepOnSplit: false,
+  inclusive() {
+    return true
+  },
+  addProseMirrorPlugins() {
+    return [tagDecoratorPlugin]
+  },
+})